1. Field of the Invention
This invention relates to an apparatus and method for quantiatively delivering food materials such as candy, whipped or custard cream, and mince, and other plastic materials, and, particularly, to an apparatus and method for delivering such materials at a uniform rate without harming their quality.
2. Prior Art
U.S. Pat. No. 3,513,477 discloses an apparatus for measuring and feeding material comprising a pair of screws disposed at the bottom of a hopper and a pair of delivering devices placed on each side of a discharge pipe. The delivering device includes a cylinder, two pairs of slots diagonally formed on the periphery of the cylinder, and a pair of vanes that are perpendicular to each other and inserted in each pair of slots so that they can slide freely through the pair of slots. A swing cam is placed between the two delivering devices so that the cam comes into dynamic contact with the vanes and causes each vane to recede to the periphery of the cylinder. The delivering devices are housed in a housing having front and rear end walls and side walls as shown in FIG. 4. In operation, as the screws rotate, they axially displace the material in the hopper. The material then progressed into the housing through an opening formed in the rear end wall and is exhausted from the discharge pipe, pushed by the vanes as the cylinders rotate while the material is measured by being introduced into a measuring compartment of a uniform capacity formed between two adjacent vanes.
As shown in FIG. 4, a cylinder is coaxially connected to the screw and thus the rotational speeds of the screw and the cylinder cannot be controlled separately.
However, if the density of the material is not uniform and/or air is entrained with the material, it is difficult to measure the weight of the material introduced into the measuring compartment. Therefore, if the density of the material is non-uniform, the apparatus of the prior art cannot deliver a material at a uniform rate. Since typical food materials or plastic materials tend to have different densities, and include air when they are supplied to a hopper, the appartus of the prior art had problems for measuring such materials.